/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package axil.engine.adapter;

import axil.api.extend.SourceAdapter;
import axil.framework.resource.ReferenceReader;
import axil.framework.resource.ResourceManager;

import java.io.Reader;
import java.util.Locale;


/**
 * The standard source adapter that Axil uses for finding modules and their
 * associated XML definitions.
 */
public class StandardSourceAdapter implements SourceAdapter {
	public StandardSourceAdapter() {
	}


	/**
	 * Provide a string reference for the given reader. The reference is
	 * intended as a diagnostic aid when problems are encountered.
	 *
	 * @param reader
	 * 	A Reader object as returned from either the module() or definition()
	 * 	methods of this class. The reader given cannot be null.
	 *
	 * @return
	 * 	Returns a reference sufficiently complete as to be unambiguous as to
	 * 	the source. For example, if the source is a file, it would be the
	 * 	absolute path to the file, not just the filename.
	 */
	public String reference(Reader reader) {
		return ((ReferenceReader)reader).reference();
	}


	/**
	 * Return a reader object for a module definition.
	 *
	 * @param ident
	 * 	The name of the module. The identifier given is never null or empty.
	 *
	 * @return
	 * 	Returns an open and ready-to-use reader object. A null value is returned
	 * 	if this adapter cannot find the module definition.
	 */
	public Reader module(String ident) {
		return ResourceManager.instance().open("stdlib/" + ident + "/module.xml");
	}


	/**
	 * Return a reader object for a definition of the given kind of object.
	 *
	 * @param module
	 * 	The module in which the named function resides. The module given is
	 * 	never null or empty.
	 *
	 * @param kind
	 * 	The type of definition desired.
	 *
	 * @param ident
	 * 	The name of the object, such as the function or operator name. This is
	 * 	the name, without any decoration. For example, "abs", not "abs()". The
	 * 	identifier given is never null or empty.
	 *
	 * @return
	 * 	Returns an open and ready-to-use reader object. A null value is returned
	 * 	if this adapter cannot find the definition.
	 */
	public Reader definition(String module, Kind kind, String ident) {
		return ResourceManager.instance().open("stdlib/" + module + '/' +
		                                       kind.name().toLowerCase(Locale.US) + '/' + ident + ".xml");
	}
}
